The development of a cure for osteoarthritis, the most common cause of pain and disability in the elderly, is difficult because of a lack of good diagnostics tests, in particular for early stages of the disease. Many candidate biomarkers are in various stages of qualification. Limited amounts of precious, well characterized serum and plasma samples are available from the Osteoarthritis Initiative and several clinical trials. Validated multiplexed immunoassays would make the best use of these precious samples. However, at present, few osteoarthritis-related biomarkers assays are available in a high-throughput multiplex format. The technical objective for Phase I of this project is the development of high throughput multiplex panels for the quantitative measurement of 16 serum biomarkers relevant for osteoarthritis and joint injury. Two panels will be developed in a 96-well 10-spot format based upon MSD's high-sensitivity MULTI-ARRAY(R) electrochemiluminescence technology. Panel A will include up to ten low abundance markers and will require 25 ul of serum. Panel B will include up to ten high abundance markers and will require 1 ul of serum. After an analytical verification, a limited number of clinical samples will be tested. In Phase II, we will expand the panels to approximately 40 assays and determine biomarker concentrations in samples from an osteoarthritis clinical trial. PUBLIC HEALTH RELEVANCE: The development of a cure for osteoarthritis, the most common cause of pain and disability in the elderly, is difficult because of a lack of good diagnostics tests, in particular for early stages of the disease. The objective of this proposal is the development of blood tests that measure many potentially useful biomarkers at the same time. This will lead to better ways to determine whether a treatment is effective earlier in the treatment regimen.